Data from: Disruption of foraging by a dominant invasive species to decrease its competitive ability

Invasive species are a major threat to biodiversity when dominant within their newly established habitat. The globally distributed Argentine ant Linepithema humile has been reported to break the trade-off between interference and exploitative competition, achieve high population densities, and overpower nests of many endemic ant species. We have used the sensitivity of the Argentine ant to the synthetic trail pheromone (Z)-9-hexadecanal to investigate species interactions for the first time. We predicted that disrupting Argentine ant trail following behaviour would reduce their competitive ability and create an opportunity for three other resident species to increase their foraging success. Argentine ant success in the control was reduced with increasing pheromone concentration, as predicted, but interactions varied among competing resident species. These behavioural variations provide an explanation for observed differences in foraging success of the competing resident species and how much each of these individual competitors can increase their foraging if the competitive ability of the dominant invader is decreased. The mechanism for the observed increase in resource acquisition of resident species appears to be a decrease in aggressive behaviour displayed by the Argentine ant, which may create an opportunity for other resident species to forage more successfully. Our demonstration of species interactions with trail pheromone disruption is the first known case of reduced dominance under a pheromone treatment in ants.

入侵物种在新定殖生境中占据优势时，会对生物多样性构成重大威胁。全球广泛分布的阿根廷蚁（Linepithema humile）被报道能够打破干扰竞争与利用性竞争之间的权衡，实现极高的种群密度，并压制诸多本土蚁类的蚁巢。我们首次利用阿根廷蚁对合成踪迹信息素（(Z)-9-十六醛）的敏感性，探究物种间的相互作用。我们预测，破坏阿根廷蚁的踪迹跟随行为会削弱其竞争能力，为另外三种本土常驻物种创造提升觅食成功率的机会。正如预测，对照组中的阿根廷蚁的生存优势会随信息素浓度升高而降低，但不同竞争型本土常驻物种间的相互作用存在差异。这些行为差异解释了观测到的竞争型本土常驻物种觅食成功率的差异，以及当优势入侵者的竞争能力被削弱时，各单个竞争者可提升多少觅食表现。观测到的本土常驻物种资源获取能力提升的机制，似乎是阿根廷蚁攻击行为的减少，这或许为其他本土常驻物种更高效地觅食创造了条件。我们通过踪迹信息素干扰探究物种相互作用的研究，是已知首个在蚁类中通过信息素处理降低入侵物种优势地位的案例。